Editing Boeing 707 (section)

===Undeveloped variants===
The 707-620 was a proposed domestic range-stretched variant of the 707-320B. The 707-620 was to carry around 200 passengers while retaining several aspects of the 707-320B. It would have been delivered around 1968 and would have also been Boeing's answer to the stretched [[Douglas DC-8#Super 60 Series|Douglas DC-8 Series 60]]. Had the 707-620 been built, it would have cost around US$8,000,000.<ref name="FI1">{{cite press release |url=http://www.flightglobal.com/pdfarchive/view/1965/1965%20-%200802.html| title=T0WARD8 200-SEAT BOEINGS| publisher=[[Flight International]]|date=March 25, 1965 |access-date=December 12, 2012}}</ref> However, engineers discovered that a longer fuselage and wing meant a painstaking redesign of the wing and landing-gear structures. Rather than spend money on upgrading the 707, engineer [[Joe Sutter]] stated the company "decided spending money on the 707 wasn't worth it". The project was cancelled in 1966 in favor of the newer Boeing 747.<ref name="MH">{{cite book |title=Boeing Widebodies |publisher=Zenith Press |author=Haenggi, Michael |year=2003 |location=Saint Paul, Minnesota |pages=[https://archive.org/details/boeingwidebodies00mich/page/15 15 and 17] |isbn=978-0-7603-0842-4 |url=https://archive.org/details/boeingwidebodies00mich/page/15}}</ref>

The 707-820 was a proposed intercontinental stretched variant of the 707-320B. This {{convert|412,000|lb|kg|adj=mid|MTOW}} variant was to be powered by four {{convert|22,500|lbf|kN|adj=mid|thrust}} Pratt & Whitney JT3D-15 turbofan engines, and it would have had a nearly {{convert|10|ft|m|adj=on}} extension in wingspan, to {{convert|155.5|ft}}. Two variations were proposed, the 707-820(505) model and the 707-820(506) model. The 505 model would have had a fuselage {{convert|45|ft|m}} longer than the 707-320B, for a total length of {{convert|198.6|ft|m}}. This model would have carried 209 passengers in mixed-class configuration and 260 passengers in all-economy configuration. The 506 model would have had a fuselage {{convert|55|ft|m}} longer than the 707-320B, to {{convert|208.6|ft|m}} in length. This second model would have carried 225 passengers in mixed-class configuration and 279 passengers in all-economy configuration. Like the 707-620, the 707-820 was also set to compete with the stretched DC-8-60 Super Series models. The design was being pitched to American, TWA, BOAC, and Pan Am at the time of its proposal in early 1965.<ref name="FI19650603">{{cite magazine |url=http://www.flightglobal.com/pdfarchive/view/1965/1965%20-%201564.html |title=Boeing 707-820: First details of the longer, faster, heavier and more powerful new 279-seat Boeing |publisher=[[Flight International]] |pages=860+ |date=June 3, 1965 |access-date=December 12, 2012 |url-status=dead |archive-date=April 20, 2016 |archive-url=https://web.archive.org/web/20160420233731/http://www.flightglobal.com/pdfarchive/view/1965/1965%20-%201564.html}}</ref> The 707-820 would have cost US$10,000,000.<ref name="FI1" /> Like the 707-620, the 707-820 would have required a massive structural redesign to the wing and gear structures. The 707-820 was also cancelled in 1966 in favor of the 747.<ref name="MH"/>